3.6. Inhibition of the AMPK Pathway Abolishes the Protective Effect of CTRP9 on VSMC-Derived Foam Cells
Considering that CTRP9 is an agonist of the AMPK pathway, we aimed to further explore the role of AMPK in the protective effect of CTRP9. To this end, the expression of antioxidant enzymes was measured after incubation with Compound C, a recognized inhibitor of the AMPK pathway. Pretreatment with Compound C notably decreased the expression of antioxidant enzymes, indicating that the AMPK pathway is essential for antioxidative enzyme expression (Fig. 6a and b). Pretreatment with Compound C significantly blocked the protective effect of CTRP9 against ox-LDL-induced VSMC-derived foam cell necroptosis, as revealed by the abnormal accumulation of mtROS and reduction in ΔΨm (Fig. 6c and d). The effects of Compound C on the necrosomes were examined using western blotting. Inhibition of the AMPK pathway by Compound C promoted cell necroptosis, as evidenced by the increased phosphorylation of RIP1 and MLKL as well as the upregulated expression of RIP3 in VSMC-derived foam cells (Fig. 6e and f). Collectively, our findings suggest that CTRP9 inhibited ox-LDL-induced VSMC-derived foam cell necroptosis through the AMPK pathway.